经皮椎体成形术的实验研究

Percutaneous vertebroplasty:an experimental study in adult corpses

目的 探讨经皮椎体成形术 (percutaneousvertebroplasty,PVP)的几个关键技术和其作用机制。方法 将骨水泥 (聚甲基丙烯酸甲酯 ,polymethylmethacrylate ,PMMA)的粉、液比例分别按 1∶1、3∶2、2∶1共 3种方式调配 ,每组 10份 ,在体外测试其聚合过程。将 4具正常成人尸体胸腰段 ,分成2组 ,1组取T12～L4共 10个椎体 ,在CT +X线透视下行经皮椎体穿刺 ,注入骨水泥 ,另 1组取T12～L4共 10个椎体 ,作抗压强度测试的对照组。将注射组和对照组分别游离成各 10个单个椎体 ,双盲法测量其纵向最大抗压强度。结果 3种比例骨水泥的稀、稠阶段持续时间及聚合时温度的升高值具有显著性差异 (P <0 0 5 ) ;合适的PMMA粉、液比例为 3∶2 ;均未发生椎弓根及椎体前缘骨皮质损伤 ,平均每个注入骨水泥 4.5ml,有 4个椎体出现椎旁静脉渗漏 ;注入PMMA的椎体的最大抗压强度比对照组提高约 38% (P <0 .0 5 )。结论 掌握适宜的PMMA粉、液比例和注射时机是PVP成功的关键因素 ;采用经椎弓根穿刺行PVP是可行的途径 ;椎体内注入PMMA可显著增强其抗压强度。

Objective To investigate the key technique factors and the mechanisms of percutaneous vertebroplasty (PVP). Methods PMMA was classified into three groups according to the ratio of powder/liquid as 1∶1, 3∶2, and 2∶1. Polymerizing process in vitro was measured respectively in each group, which included 10 samples. Twenty vertebrae from T12 L4 in 4 adult corpses were randomly distributed into 2 groups. In one group, PVP was performed under monitoring by combined CT and C arm X ray machines. All vertebrae were dissected into individual vertebra and the ultimate compressive strength was measured in double blind tests. Results The period of the polymerizing process and the temperature changes during the polymerizing among 3 groups with different ratio of powder/liquid were significantly different. The ratio of 3/2 was the proper regimen for injection. Punctures were successfully reached in one set of puncture in all vertebrae but one, with 4.5 ml of PMMA in average injected in each vertebra. Prevertebral leakage of PMMA was demonstrated in 4 of 20 vertebrae. The ultimate compressive strength increased in 38% in the experimental group compared with that of the control group. Conclusions Proper ratio of powder/liquid and injection time of PMMA is the key technique for PVP. The puncture route of trans arch of vertebra is accessible for PVP. It is proven in this study that the ultimate compressive strength of vertebra enhances greatly after PVP.